June 1, 2011

U.S. Nuclear Operations in a Post-Fukushima World

By Kathryn M. Sutton and Stephen J. Burdick

On March 11, 2011, the magnitude 9.0 Tohoku earthquake struck northeast Japan and was followed by a large tsunami. Both events damaged the Fukushima Daiichi nuclear plant. These natural forces appear to have eliminated first the offsite power and then onsite emergency diesel generators. Explosions at the site followed. As a consequence of these and other events, the Fukushima plant experienced significant damage to plant systems, structures, and equipment.

Perhaps more than for any other industry, a nuclear accident in any part of the world affects nuclear operations elsewhere. Such an incident necessarily and inevitably results in industry self-examination, heightened regulatory oversight, and third-party scrutiny.

The full extent of any resulting regulatory changes will not be clear until more is known about the earthquake, the tsunami, and the resulting performance of the Fukushima plant. A few important conclusions, however, already have become clear. First, the existing U.S. nuclear regulatory regime is robust and already addresses the contributors to the Fukushima event. Second, the U.S. nuclear industry will learn from the event. Finally, U.S. nuclear licensing activities should continue unabated, as the underlying regulatory regime fully accommodates the lessons learned from Fukushima and other events.

Current U.S. Nuclear Regulations

The U.S. nuclear regulatory regime is robust and dynamic. Though specific regulatory requirements will be evaluated and reexamined in great detail in the coming months and years in response to the Fukushima event, they already address key issues raised by that event, including:

• Reactor siting criteria, such as seismology and hydrology.
• Designs that protect against natural phenomena and accident scenarios.
• Ability to withstand a “Station Blackout” event (loss of all AC power).
• Multiple redundant heat removal means during an accident.
• Separate mitigative strategies intended to maintain or restore core cooling, containment, and spent fuel pool cooling capabilities in the event of loss of normal cooling systems.
• Emergency planning.